Problem: Factor the following expression: $50x^2 - 72$
We can start by factoring a ${2}$ out of each term: $ {2}({25x^2} - {36})$ The second term is of the form ${a^2} - {b^2}$ , which is a difference of two squares so we can factor it as ${2}({a} + {b}) ({a} - {b})$ What are the values of $a$ and $b$ $ a = \sqrt{25x^2} = 5x$ $ b = \sqrt{36} = 6$ Use the values we found for $a$ and $b$ to complete the factored expression, ${2}({a} + {b}) ({a} - {b})$ So we can factor the expression as: ${2}({5x} + {6}) ({5x} - {6})$